In constructing roads, buildings, bridges and the like, it is advantageous to use materials that are long lasting, easy to work with and cost effective. These materials include such things as timbers, brick, steel and concrete. Concrete is a preferred material because of its strength, permanency and relatively low cost when compared with other building materials. As is well known, concrete is made up of coarse and fine aggregate, such as gravel and sand, water and a cementing agent which is employed to bond the aggregate materials to one another. By varying the amount of the above ingredients, the concrete can be formulated with different properties. For example, by employing a reduced water to cement ratio, the strength of the concrete is maximized. These different concrete properties are employed depending upon the application and the stress expected to be received by the finished concrete.
It is also known to mix concrete with liquid additives to enhance particular properties of the concrete. For example, additives can be included with the mix of cement, aggregate and water to: lower the weight or density of the concrete; increase the thermal insulative qualities; add color; and add properties that are more resistant to particular natural conditions such as freezing and humidity. These additives include, but are not limited to, calcium chloride, liquid air (entraining), calcium substitutes, finishing agents, accelerants and retarders for drying, and plasticizers.
Previously, these additives were introduced with the concrete mix by manual methods. These methods employed a site tube within an intermediate vessel for receiving the liquid additive and then dumping the contents of the intermediate vessel into the concrete mix. There are also other types of mechanically operated dispensers to obtain the desired volume of additive.
Unfortunately, the aforementioned methods for mixing liquid additives with the concrete mix are inaccurate and detrimental to the manufacture of a superior concrete product. These manual methods of determining the proper volume of additive are also time consuming and unrepeatable where different types of concrete are required to be mixed in succession. The consequences of an improper volume of liquid additive can result in defective concrete thus requiring a large expense in and associated method for introducing liquid additives into a concrete mix. Furthermore, there is a need for an apparatus and associated method which ensures that the proper volume of liquid additive can be repeatably and reliably introduced to different batches of concrete mix.